The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Thermostatic mixers, which are suited to handling a large flow do not function properly if the flow that is demanded from them is much smaller than the maximum flow for which they are designed, which occurs, for example, when a thermostatic mixer intended for supplying a system with multiple shower units is used to supply a single shower unit. Under these circumstances, thermostatic mixers lose their stability and begin to oscillate so that the water flow piped from them is subjected to constant changes in the ratio of cold to warm water and thus sustains temperature fluctuations, which are unpleasant for the user and can even be harmful. This disadvantage can be eliminated by having the flow of cold water supplying the thermostatic mixer opposed by a resistance when small flows of mixed water are demanded, while suppressing or reducing this resistance when large flows of mixed water are demanded. This process is triggered automatically by devices for dynamic control of flow, in which it is provided that the passage cross section made available for the incoming cold water is to be reduced when the admitted flow is reduced and a larger passage cross section is to be restored when a greater flow is demanded. However, the prior art devices for dynamic control of flow generally have the disadvantage of featuring pistons that are acted upon in one direction by the pressure of the incoming water and in the other direction by a return spring. The load of the spring must therefore be adjusted according to the inlet pressure of the cold water. This means that on one hand, the device must be adapted during installation to the pressure conditions present in the system for the sake of correct functioning, while on the other hand, the device no longer functions properly when considerable variations in the inlet pressure of the cold water appear.